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Electronic Dictionary

R1

radar
Acronym for "radio detection and ranging" A system that measures the distance and direction of objects.

radioastronomy
Branch of astronomy that studies the radio waves generated by celestial bodies and uses these emissions to obtain information about them.

radio broadcast
Transmission of music, voice and other information on radio carrier waves that can be received by the general public.

radiocommunication
Term used to describe the transfer of information between two or more points by use of radio or electromagnetic waves.

radio-frequency amplifier
Amplifier having one or more active devices to amplify radio signals.

radio-frequency generator
Generator capable of supplying RF energy at any desired frequency in the radio-frequency spectrum.

radio-frequency probe
Probe used in conjunction with an AC meter to measure radio-frequency signals.

RC
Abbreviation for "resistance capacitance" also abbreviation for "radio controled" as in "RC model airplanes."

RC time constant
Product of resistance and capacitance in seconds.

reactance
Symbol "X". Opposition to current flow without the dissipation of energy. Example: The opposition provided by inductance or capacitance to AC current.

reactive power
Also called imaginary power or wattless power. It is the power value in "volt amps" obtained from the product of source voltage and source current in a reactive circuit.

real number
Number having no imaginary part.

receiver
Unit or piece of equipment used to receive information.

recombination
Process by which a conduction band electron gives up energy (in the form of heat or light) and falls into a valence band hole.

rectangular coordinates
A Cartesian coordinate of a Cartesion coordinate system whose straight-line axes or coordinate planes are perpendicular.

rectangular wave
Also known as a pulse wave. A repeating wave that only operates between two levels or values and remains at one of these values for a small amount of time relative to the other value.

rectification
Process that converts alternating current to direct current.

rectifier
Diode circuit that converts alternating current into pulsating direct current.

reed relay
Relay consisting of two thin magnetic strips within a glass envelope. When a coil around the envelope is energised, the relay,s contacts snap together making a connection between leads attached to the reed strips.

regenerative feedback
Positive feedback. Feedback from the output of an amplifier to the input such that the feedback signal is in phase with the input signal. Used to produce oscillation.

regulated power supply
Power supply that maintains a constant output voltage under changing load conditions.

regulator
Device or circuit that maintains a desired output under changing conditions.

relay
Electromechanical device that opens or closes contacts when a current is passed through a coil.

relative
Not independent. Compared with or with respect to some other measured quantity.

relaxation oscillator
Free running circuit that outputs pulses with a period dependent or one or more RC time constants.

reluctance
Resistance to the flow of magnetic lines of force.

remanence
Amount a material remains magnetized after the magnetizing force has been removed.

residual magnetism
Magnetism remaining in the core of an electromagnet after the coil current is removed.

resistance
Symbolized "R" and measured in ohms. Opposition to current flow and dissipation of energy in the form of heat.

resistive power
Amount of power dissipated as heat in a circuit containing resistive and reactive components. True power as opposed to reactive power.

resistive temperature detector
(RTD) Temperature detector consisting of a fine coil of conducting wire (such as platinum) that will produce a relatively linear increase in resistance as temperature increases.

resistivity
Measure of a material's resistance to current flow.

resistor
Component made of material that opposes flow of current and therefore has some value of resistance.

resistor color code
Coding system of colored stripes on a resistor to indicate the resistor's value and tolerance.

resonance
Circuit condition that occurs at the frequency where inductive reactance (XL) equals capacitive reactance (XC).

Keywords : Electronic, Dictionary, Description, Info, What, Whatis, Introduction
Writer : delon  |
5 Jan 2006 Thr   
|  6.932 Views
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